Automatic compression control for engines



J 1940- R. D. WATSON 2.209,496

AUTOMATIC COMPRESSION CONTROL FOR ENGINES Filed Feb. 15, 1939 45]1eets-Sheet l July so, 1940.

R. D. WATSON AUTOMATIC COMPRESSION CONTROL FOR ENGINES Filed-Feb. 15.1959 KICHAEO fl VVArso/v,

4 Sheets-Sheet 2 July30,1940- R. ,nfwATsofi 2209,496

- I AUTOMATIC COMPRESSION CONTROL FOR ENGINES Filed Feb. 15,- 1959 4Sheets-Shet 4 gwu /l vm 110 I R/CHAQD 0. T WWso/v,

I Patented July 30, 1940 me sTATss PATENT oFFics Richard D. was,Ang'eles, assignor v of one-half to George Yates, Glendale, Calif.

Application February 15, 1939, Serial No. 256,497

21 Claims. (01.123-182) This invention relates to mechanisms forcontrolling the compression of'engines, and particularly to that type ofmechanism which relieves the engine of compression to permit a startingdevice to impart momentum to the engine parts under relatively lightloads, and which especially of the internal combustion type, tofacilitate their starting.

It is another object of the invention to provide a device capableoffdiscontinuing the operation of an engine through control of itscompression.

A further object of the invention is to provide a device capable ofcontrolling engine compres- 2o sion from a relatively remote point.

Still another object of the invention contemplates a safety device whichwill automatically discontinue engine operation in the event of defectsarising in, or failure of, the lubricating sys- Another object or theinvention is'to prevent operation of an engine having a defectivelubrieating system; and to prevent its starting until the defect hasbeen r'emedied.-

Another object of the invention is to safeguard "an internal combustionengine from i possible -damage due to overheating.

A further object of the invention is to provide means for discontinuing,engine operation upon excessive heating or complete failure of thecooling fluid.-

Another object of the invention is the provision of an automatic systemfor substantially simultaneously controlling the compression inall ofthe cylinders of an" engine. -A further object of the invention is toprovide means for governing the compression in each cylinder of amultiple cylinder engine by means controllable from acommon source Thisinvention possesses many other advantages and hasother objects whichmaybe made more easily apparent from a consideration of severalembodiments of the invention. For this purpose there are shown a numberof forms in the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be under-, stoodthat this detailed description is not to be taken in a limiting sense,since the scope of the I invention isbest defined by the appendedclaims. Referring to the drawings: Figure 1 is a diagrammatic viewillustrating a system of compression control with parts shown incompression releasing position. Figure 2 is a view similar to Figure 1showing the partsJna position permitting normal engine operation.

Figure 3 is a section through a modified constructional arrangement ofthe servo-motor and 10 v valve control embodied in the system'shown inFigure 1.

Figure 4 is a transverse section taken as indi-' cated by the line 4-4of Figure 3.

Figure 5 is a diagrammatic view illustrating 1|,

the system of Figure 1 as applied to a multiple cylinder engine, certainparts being shown in compression releasing position, and

Figure 6 is a view similar to Figure 5, with parts being shownin,engineoperating position. go The system disclosed in Figures 1 and 2of the drawings includes the usual cylinder Iii of an" engine,preferably of the internal combustion type,ihaving inlet and outletvalves, only the out let valve It being shown in the drawings. The '25valves are operated from a cam shaft through the instrumentality of camsl6 and i1 normally engageable with valve tappets I8 and i9 producingreciprocation of push rods and 2|, which in turn oscillate rocker armsin a usual and well-known manner, the outlet valve rocker arm 22 beingthe only one shown in the'drawing.

The cam shaft I5 is driven from the engine crank I shaft (not shown),and is journaled in bearings 24 and 2B whichare supplied with-lubricantby a means of a pump 26 having communication with the bearings throughthe conduits 21. This pumpis driven from the engine cam shaft l5 throughsuitable mechanical means such as the chain 28 connecting sprockets 29and 30 carried onthe a respective cam and pump shafts, and pumpslubricantfrom the usual engine crank case (not shown) through thestrainer'3l and intake pipe 32 and exhausting it into the conduitsiz'ifor lubricating various parts of the engine mecha- Engines having arelatively high compression ratio can be started against this highcompression pressure only by imposing a very heavyload on the batteryand starting motor. This is par- 5Q ticularly true in connection'wlthDiesel engines,

which have compression ratios of as'much as 18 to 1. The presentinvention seeks to provide a systemvand mechanism obviating the need forstarting the engine against this high compres- 5 l the open valve.

sion load by relieving the engine of its compression while momentum isimparted to the engine by a starting device operating against a relativelight load. After sufficient kinetic energy has been stored in thestarting motor and the engine parts, the engine compression can bere-established in order to produce its self-operation.

In the specific example disclosed in Figures 1 and 2, an element isinterposed in one of the valve actuating means to prevent the valve fromclosing when its operating cam is in valve closing position. Thiselement is constituted by a lever finger or arm having an end 36cooperable with a supplementary cam 31 fixed to the cam shaft I5. Thiscam 31 is preferably small enough to fall within the base circle of thecam l6 in order to have no effect upon the valve tappet l8 until thelever finger 35 has been interposed between the tappet l8 and thesupplementary cam 31. It will be noted that the supplementary cam lobeextends substantially oppositely to the tappet lifting portions of themain cam 16 to prevent complete lowering of the tappet I8 when the leverfinger 35 is interposed between the supplementary cam 31 and the tappetI8, and consequently, prevents closing of the associated valve ll.Whenever the lever finger 35 is in such interposed position theassociated valve I i will be prevented from closing completely since thecam contacting surface pre-' sented by the finger end 36 extends beyondthe base circle of the main cam I6, and a medium within the cylinder II]will be incapable of being compressed due to its ability to escapethrough Removal of the lever finger 35 from engagement with thesupplementary cam 31 will permit normal operation of the valve mechanismand the creation of the usual compression pressure within the cylinder10.

The particular position occupied by the lever finger 35 with respect toe supplementary cam 31 is determined by conditions of operation of theinternal combustion engine. So long as the engine is rotating properly,the lever finger 35 will be maintained out of the path of movement ofthe supplementary cam 31 and free it. from any restraining movement uponthe valve tappet l8.

But in the event that the engine is stationary, or certain undesirableconditions arise in connection with its operation, the lever 35 will bemoved longitudinally along the cam shaft l5 into radial contact with thesupplementary cam 31.

The aforementioned functions are achieved in the instant case bymounting the lever 35. for oscillation upon a shaft 40 having one end400. forming a piston slideable within a fiuid cylinder 42. Fluid underpressure can be conveyed from the lubricating conduit lines 21, or fromone of the engine bearings, by conducting it through the branch line 43,communicating with an end of the fluid cylinder 42. It will therefore beseen that the rotation of the crankshaft, cam shaft, or other rotatableparts of the engine will operate the lubricating pump 26 to force fluidvto the various bearings and other parts of the engine, and also exert apressure upon the fiuid within the cylinder 42 to move the piston 40atherein. This movement will be communicated to the lever 35 since it isrestrained from axial movement with respect to the piston shaft 40 bythe oppositely disposed collars 45 and 46 pinned or otherwise suitablysecured to the shaft 40. In the event that the piston40a movessuiiiciently, the lever 35 will be disengaged from the supplementary cam31 and permit normal operation of the associated valve mechanism.However, the shaft 4|) of the shaft 40 piloted within this cylinder. The

compression of the spring can be determined by means of the adjustingplug 52 threaded intothe outer end of the cylinder 5|.

The operation of the parts so far described can now be understood. Astationary condition of the engine results in the lack of pressure inthe lubricating system in view of the fact that the pump 26 is not beingdriven. The helical spring can therefore urge the lever finger 35 into aposition in which its outer end .36 will engage with both thesupplementary cam 31 and the valve tappet i8, preventing closing of theassociated valve II in the manner aforementioned. If the engine iscranked by a suitable starting device, the pump 26 will be rotated andpressure built up in the fluid system. The more rapid the motion of theengine parts, the greater the speed of the pump and also the pressuregenerated by it. A condition is eventually reached wherein the engineparts are rotating at a sufficient speed to overcome any startingcompression that can be built up in the cylinder 10. When this conditionis developed, sufiicient pressure will also be produced in thelubricating system and in the fluid cylinder 42 to force the shaft 40and its piston 40a outwardly against the action of the spring 50 andfree the lever from contact with the supplementary cam 31. Thecompression then obtained in the cylinder in will be sufiicient toignite injected fuel (in the case of.a Diesel engine) or ignition ofcompressed fuel (in the case of an engine operated on the Otto cycle).So long as the engine is operating under its own power, the lubricatingpump 26 will generate sufiicient pres sure to hold the shaft 40 and itspiston 40a in proper position against the action of the spring 50 andmaintain the lever finger 35 out of compression releasing position withrespect to the supplementary cam 31 and the valve tappet l3. But uponstopping of the engine or loss of lubricating pressure in any othermanner the spring 50 can reestablish radial engagement between thesupplementary cam 31 and lever finger 35 and prevent further operationof the engine by continued relieving of its compression. The leverfinger 35 is held in'proper radial contact with the supplementary cam 31by means of the helical spring 55 connected to the lever extension 56and to some stationary member.

Since the system described is dependent upon the pressure of thelubricating fluid for permitting self-operation of the engine, it willbe apparent that loss of this pressure will produce stopping of theengine by relieving its compression through the interposition of thelever finger 35 between the supplementary cam 31 and the valve tappetl8. Accordingly, should the pump fail, or leakage occur in the lubricantsystem, or the lubricant supply in the crank case sump become exhausted,the pressure in the fluid cylinder will drop and the engine stoppedbefore any damage This can be accomplished by instem 64, or a suitablehandle fixed thereto (Figures and 6), which action will permit thelubricating fluid to escape to the engine sump (not shown) through thevalve inlet and outlet conduits I1 and 68, and thereby permit the spring50 to position the lever finger 35 in radial contact with thesupplementary cam 31 to relieve the engine of compression by preventingclosing I of the valve The pressure relief valve 60 can also be operatedin other ways, as by connecting a suitable remotely controlledsolenoidwith its stem (not shown). It can also be controlled remotely independance upon the operating temperature of the engine, being cause toopen in the event of excessive heating of engine cooling elements, suchas cooling water. In the specific example shown in Figure 1, athermostat bulb 10 is connected in the water cooling jacket 1| of thecylinder head 12, with a line 13 leading from the bulb 10 to anexpansible bellows 16 contained within a housing 15. One end of 'thebellows is fixed to the housing in such a manneras to form a leakproofjoint therewith, and the other end operates against a push rod 16.slideable in a guide sleeve 11 fixed to an intermediate partition 18 inthe housing 15. Expansion of the fluid in the thermostat bulb 10 and itscommunicating line 13 upon increase in the temperature of the coolingwater in the jacket 1|, will tend to. force the push rod 18 downwardlyagainst the action of a spring 19 encircling the rod 1% and engage'ablewith a head 80 secured to its upper end and also with a nut 8|adjustably threaded on the guide sleeve. The push rod 16 extendsvthroughthe housing and .is operatively connected with a lever'82 fulcrurned ona suitable stationary supporting bracket 83.

The connection may be in the form of a slot 84 in one end of the leverreceiving a looped portion 85 ofthe push rod 16 to provide a lost motiontherebetween. The other end of the lever is connected with the valvestem 64 through the pivotal connection 86.

As the temperatureincreases in the cylinder head water jacket 1|, thefluid in the thermostat bulb 10 will expand, distending the bellows 14'downwardly and producing corresponding movement of the push rod 16against the action of thespring 19. No motion will be imparted to thelever 82 and relief valve stem 66 until the push rod'16 engages with thebottom of the lever slot 86. Such engagement will only occur upon anexcessive rise in the jacket cooling water temperature, which conditionwill effect a rocking of the lever 82 on its fulcrum 82a and a raisingof valvehead 63 from its seat 62, which permits venting of the lubricantto the crank case sump through the line 68, and decompression of theengine by movement of the lever finger-3S into proper cam engagingposition un- I der the influence of the spring 50.

In efiect, the fluid cylinder and piston device 40, 42, etc., and thereturn spring mechanism 60,

. it, etc. constitute a servo-motor operable in ac- The limits of travelof the lever 35 and the piston cordancewith certain definite engineconditions.

shaft 40 can be determined by utilizing the restraining collars "and 46as stops abutting against the ends of the respective piston and springcylinders 42 and SI. The range of movement *is chosen so that abuttingof the collar 46' against the fluid cylinder 42 occurs upon completeengagement of the lever finger 35 with the supplementary cam 31, whileabutting of the other collar 45 against the end of the spring cylinder5| occurs upon complete disengagement of the lever 35 from the cam 31,as shown in Figure 2.

structural organization. In this figure, the cam shaft |5a is'rotatablein suitable bearings 24a and .25a supplied with lubricant through theducts 21a and 21b. The servo-motor S is shown attached directly to partsof the engine housing 90 by bolts ill, the fluid pressure cylinder 42acommunicating with the cam shaft bearing a through the fluid reservoir42b contained within the servo-motor housing, and the aligned ducts 9|and 92 in said housing and the engine housing 90. The shaft a carryingthe lever 35a and confining collar stops a and 46a heretofore described,includes a piston portion 6% within the cylinder 42a and-another portion400 slideable within a bore 5|a provided in the end of the servo-motorhousing. This bore is closed by a terminal cap 95 secured to theservo-motor housing by screws 96, the cap being provided with a recess91 receiving a helical spring 98 also confined within a recess $9 in theend of the shaft 40a. One end of the spring 98 abuts against a plug 52athreaded into the cap 95, whereby the spring. tension can be adjusted.The lever finger 35a is maintained against the cam shaft |5a or againstthe supplementary cam 31a by means of the spring ||l| attached to thelever extension 56a and to an anchor screw I02 threadedly secured in theservo-motor housing.

The operation of the parts shown in the modification of Figures 3 and 4is the same as that described inconnection with'Figures l and '2.However, the relief valve a is formed integrally with the servo-motorhousing, its body 6|a extending from the housing and its inlet 61aopening into the reservoir or manifold 42b. The valve outlet passage orconduit 68a extends through the servo-motor housing, communicating withthe crank case sump. The-valve head 63a, stem 64a, encircling spring86a, and threaded plug 65a are substantially the same as described inconnection with Figures 1 and 2 but the valve is adapted to be operatedmanually through the handle I05 instead of the automatic means shown anddescribed in connection with Figures 1 and 2.

As shown in Figures 5 and 6, the system is also applicable'for use inconnection with multiple cylinder engines, efiectively controlling com-'pression' in each and every one of the engine cylinders. The lubricatingpump I I0, relief valve strainer H2, etc., occupy the same relativepositions as described in connection with Figures 1 and 2. The cam shaftH3 is disclosed as being provided with a plurality of pairs of cams,each pair consisting of a cam lid for controlling an inlet valve and acam M5 for controlling an the springs I41.

the same relationship with respect to the exhaust cam as described inconnection with Figures 1 and 2. Similarly, a lever finger I26 can bemoved into radial contact with each supplementary cam- I to control theengine compression. Each lever is oscillatably mounted on a shaft I21slideable in the guides I28 and I29 suitably secured to the engine orsome convenient stationary support. As described above in connectionwith Figures 1 and 2, collars I30 and I3I are fixed to each shaft I21and are positioned on opposite sides of the lever finger I26 to preventits axial movement with respect to the slideable shaft I21 and also toact as stops, limiting the extent of travel of the shaft I21 in itsguides I26 and I29. Thus, when the collar I3I is abutting against theguide I29, the lever finger is in contact with the supplementary camI25, functioning to relieve the cylinder from compression. Axialmovement of the shaft I21 to cause abutting of the collar I30 againstthe guide I28, insures movement of the lever finger out of contact withthe supplementary cam and permits compression of whatever medium is inthe engine cylinder.

The lever fingers I26, I26 are mounted for independent oscillation topermit their operation in conjunction with the supplementary cams I25,I25, which are angularly'displaced on the cam shaft with respect to oneanother in view of the usual angular displacement of the exhaust camsrelative to onewanother. For this reason, a separate shaft I21 isprovided for oscillatably mounting each of the lever fingers. However,

the axial positions of the levers with respect to the supplementary camsare governed by a common servo-motor I operable substantiallysimultaneously upon all of the slideable shafts. This servo-motorincludes a cylilnder I36 in communication with the engine lubricatingsystem, there being a piston I39 slideable within the cylinder I36 and apiston rod I 40 connected thereto and extending through the cylinder forreciprocation in the guideways I28, I29. A yoke I4I for each cylinder ispinned or otherwise suitably secured to the extended piston rod I40,each yoke being operable upon a flanged collar I42 slideable upon theshaft 521. Each shaft I21 carries collars I45 and I 450. pinned to itsends.- A spring I46 encircling the rod I 21 between one of the guidesI26 and a collar I45a, serving to urge the lever finger I26 into radialcontacting position with the supplementary cam I25. A spring I41 of muchgreater compressive strength than the spring I46 encircles the shaft I21between the other guide I-26 and the flanged collar I42, tending toslide this collar along the shaft I21 into contact with the fixed collarI45, and thereafter slide the shaft I21 in its guideways I28, I29, tomove the lever finger I26 out of contact with the supplementary cam I25.

When lubricating pressure is lacking system, a spring I50 encircling thepiston rod I40 within the cylinder I36 will move the piston I39towardthe inlet end of the cylinder and correspondingly slide theflanged collars I42 along their respective rods I21 against the actionof This relieves the effect of'these springs upon the slideable rods I21and the lever fingers I26, permitting the springs I46 of lessercompression to move the rods I21 and position the fingers I26 intoradial contact with the supplementary cams I25, thereby relieving all ofthe cylinders of compression. Upon the creation ofsuflicient pressure inthe lubricating system the piston I39 will be moved in the cylinder I36in the against the action of its engaging spring I50 and will move theyokes I4I away from the,

flanged portions of the collars I42, allowing the springs I41 of greatercompressive strength to force the flanged elements I42 against thecollars I45 on the shafts and move the lever fingers I26 out of radialcontact with the supplementary cams I25, permitting the establishment ofcompression in all of the engine cylinders and its susequentself-operation.

It will be appreciated that the multiple compression relieving systemcan also have the same safety and control features described inconnection with the single cylinder system of Figures 1 and 2.

I claimz l. A system for controlling thecompression of engines havingvalve actuating mechanism including means adapted to be interposed insaid valve actuating mechanism for preventing clos ing of a valveactuated thereby, means tending to interpose said first means, and meanscontrollable by theengine operation for maintaining said first-means innon-interposed position.

2. A system for controlling the compression of engines having valveactuating mechanism ineluding means adapted to be interposed in saidmovement of said actuating means, means oper- I able by said engine forimparting pressure to a fluid, and means for conducting said fluid underpressure to said pressure responsive means, whereby said interposedmeans is movable from the path of movement of said valve actuatingmeans. 4. A system for controlling the compression of engines havingvalve actuating means including means adapted to be interposed in saidmeans for preventing closing of a valve adapted to be actuated therebyresilient means for interposing said means, fiuid pressure responsivemeans for positioning said interposed -means out of the path of movementof said actuating means, means operable by said engine for lubricatingengine parts by fluid under pressure, and means for conducting saidfluid under pressure to said pressure responsive means, whereby saidinterposed means is movable from the path of movement of said valveactuating means. 5. A system for controlling the compression 0 engineshaving valve actuating means including means adapted to be interposed insaid means for preventing closing of a valve adapted to be actuatedthereby, means responsive to motion of engine parts for shifting saidinterposed means from the path of movement of said actuating means, andcontrol means for determining the position of said interposed means withrespect to 2,209,49e for preventing closing of a valve adapted tobeactuated thereby resilient means for interposing said means, fluidpressure responsive means for positioning said interposed means out ofthe path of movement of said aetuatingmeans, means operable bysaidengine for imparting pressure to-a fluid, means for conducting saidfluid under pressure to said pressure responsive means, whereby saidinterposed means is movable from thepath of movement of said valveactuating means, and valve means for decreasing the pressure of saidfluid to permit positioning of said interposed means in the path ofmovement of said valve actuating means.

'7. A system'for controlling the compression of engines having valveactuating means including 'means adapted to be interposedin said meansfor relieving said engine of compression by preengines having valveactuating means including means adapted to be interposedin said meansfor preventing closing of a valve adapted to be actuated thereby, fluidpressure responsive means for positioning said interposed means in andout of the path of movement of said actuating means,

means operable by said engine for imparting pres-. sure to a fluid,means for conducting said fluid under pressure to said pressureresponsivemeans,

whereby said interposed means is movable from the path of movement ofsaid valve actuating means, valve means for decreasing the pressure ofsaid fluid to permit positioning of said interposed means inthe path ofmovement of said valve actuating, means, and means responsive to acharacteristic of an engine cooling means for operating said valvemeans.

9. A system for controlling the compression of an-engine having aplurality of cylinders, valves cooperable with said cylinders forcontrolling engine operation, individual means for actuating a valve foreach cylinder, separate means adapted to be interposed in saidindividual means for relieving its associated cylinder of compression bypreventing closing of its valve, and means responsive to motion ofengine parts for shifting said interposed means from the path ofmovement of said actuating means.

10. A systemfor controlling the operation of an engine having a cylinderand valve cooperable therewith for controlling the compression therein,valve operating means comprising cam means, means operativeiy connectingsaid cam means with said Valve, and means adapted to I means foropposing the action of said fluid under be interposed between said cammeans and connecting means for preventing closing of said valveregardless of the position of said cam means.

11. A system for controlling the operation of an engine having rotatablemeans, a cylinder and cooperable valve for controlling the compressionin said cylinder, valve operating means comprising cam means and meansoperatively connecting said cam means with said valve, means adapted tobe interposed between said cam means and connecting means for preventingclosing of said valve regardless of the position of said cam means, andmeans responsive to 5 rotation of said rotatable means for shifting saidinterposed means to permit closing of said valve.

12. A system for controlling the operation of an engine having rotatablemeans, a cylinder and cooperable valve for controlling the compressionin said cylinder,valve actuating means comprising a cam shaft carrying acam, means operatively connecting said cam with said valve, meansadapted to be vinterposedbetween said cam shaft and connecting means forpreventing closing of said valve regardless of the position of said cam,fluid pressure responsive means for shifting said interposedmeans topermit closingof said valve, means responsive to rotation of saidrotatable means for imparting pressure to a fluid, and means-forconducting said fluid under to be interposed between saidcam means andconnecting means for preventing closing of said valve regardlessof theposition of said cam means,

and servo-motor means responsive to rotation of said rotatable means forshifting said interposed means longitudinally 'of said cam means topermit closing of said valve.

14. A system for controlling the operation of an engine having acylinder and cooperable valve for controlling the pressure in saidcylinder, valve operating means comprising cam means and meansoperatively connecting said cam means with said valve, lever meansadapted to be interposed between said cam means and connecting means forpreventing closing of said valve regardless of the position of said cammeans, and servo-motor means mounting said lever means foroscillation'and adapted to shift the same longitudinally of said cammeans to permit closing of said valve.

15. A system for controlling the operation of an engine having acylinder and cooperable valve for controlling the pressure in saidcylinder, a cam shaft carrying cam means, means operativeiy connectingsaid cam means with said valve, lever means adapted to be interposedbetween said cam means and connecting means for pre-. venting closing ofsaid valve regardless. of the position of said cam means, fluid pressureresponsive means mounting said lever means for oscillation, means forimparting pressure to a fluid, and means for conducting'said fluid underpressure to said pressure responsive means to shift said lever meanslongitudinally of said cam shaft away from said camv means to permitclosing of said valve. 1

16. A system as defined in claim 15, including pressure tending tomaintain said lever means in interposed position.

17. A system for controlling the operation oi an engine having acylinder and cooperable valve for controlling the pressure in saidcylinder, a

position of said cam means, means for imparting pressure to a fluid, andmeans for conducting for shifting said piston and lever meanslongitudinally of said cam shaft and away from said cam means to permitclosing of said valve.

18. A system for controlling the operation of an engine having rotatablemeans, a cylinder and cooperable valve for controlling the compressionin said cylinder, a cam shaft carrying cam means, means operativelyconnecting said cam means with said valve, a fluid cylinder, a pistonslideable in said fluid cylinder,- lever means oscillatably mounted onsaid piston and-adapted to be interposed between said cam means andconnecting means for preventing closing of said valve regardless of theposition ofsaid cam means, a pump driven by said rotatable means forimparting pressure to a lubricant, means for conducting said fluid fromsaid pump to said fluid cylinder for shifting said piston and levermeans longitudinally of said cam shaft and away from said cam means topermit closing of said valve.

19. A system as defined inclaim 18, including means for opposingmovement of said piston under the action of said fluid and urging saidlever means to interposed position.

20. A system for controlling the compression of an engine having aplurality of cylinders, valves cooperable with said cylinder forcontrolling engine operation, individual means for actuating a valve foreach cylinder, a camshaft said fluid under pressure to said fluidcylinder carrying a plurality of cam means angularly disposed withrespect to each other, a lever adapted to be interposed between each ofsaid cam means and said individual means for relieving its associatedcylinder of compression by preventing closing of its valve, a separateshaft oscillatably supporting a lever ,for movement longitudinally ofsaid cam shaft to and from its interposed position, and common means forsimultaneously shifting said shafts longitudinally.

21. A system for controlling the compression of an engine having aplurality of cylinders, valves cooperable with said cylinders forcontrolling engine operation, individual means for actuating a valve foreach cylinder, a cam shaft carrying a plurality of cam means angularlydisposed with respect to each other, a lever adapted to be interposedbetween each of said cam means and said individual meansforrelieving itsasso- RICHARD D. WATSON.- 30

